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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>Use and Implementation of Curses Interfaces</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><blockquote><h2>Use and Implementation of Curses Interfaces</h2><P>See <a href="u018f.htm">Corrigendum U018</a>.<P><xref type="1" name="interface"></xref>Each of the following statements applies unless explicitly statedotherwise in the detailed descriptions that follow. If an argument to afunction has an invalid value (such as a value outside the domain of thefunction, or a pointer outside the address space of the program, or anull pointer), the behaviour is undefined. Any function declared in aheader may also be implemented as a macro defined in the header, so a libraryfunction should not be declared explicitly if its header is included.Any macro definition of a function can be suppressed locally byenclosingthe name of the function in parentheses, because the name is then notfollowed by the left parenthesis that indicates expansion of a macrofunction name. For the same syntactic reason, it is permitted to takethe address of a library function even if it is also defined as a macro.The use of the C-language<B>#undef</B>construct to remove any such macro definitionwill also ensure that an actual functionis referred to. Any invocation of a library function that is implementedas a macro will expand to code that evaluates each of its argumentsexactly once, fully protected by parentheses where necessary, so it isgenerally safe to use arbitrary expressions as arguments. Likewise,those function-like macros described in the following sections may beinvoked in an expression anywhere a function with a compatible returntype could be called.<p>Provided that a library function can be declared without reference to anytype defined in a header, it is also permissible to declare thefunction, either explicitly or implicitly, and use it withoutincluding its associated header.If a function that accepts a variable number ofarguments is not declared (explicitly or by including its associatedheader), the behaviour is undefined.<p>As a result of changes introduced in this version of the <B>Curses</B> specification, applicationwriters are only required to include the minimum number of headers.Implementations of XSI-conformant systems will make all necessarysymbols visible as described in the Headers section of this document.<h3>C Language Definition</h3>The C language that is the basis for the synopses and code examples in thisdocument is <I>ISO C</I>, as specified in the referenced ISO C standard.<I>Common Usage C</I>, which refers to the C languagebefore standardisation, was the basis for previous editions of thisspecification.<h3>The Compilation Environment</h3><xref type="2" name="comp"></xref>Applications should ensure that the feature test macro _XOPEN_SOURCE isdefined before inclusion of any header. This is needed to enable thefunctionality described in this document, and possibly to enable functionalitydefined elsewhere in the Common Applications Environment.<p>The _XOPEN_SOURCE macro may be defined automatically by thecompilation process, but to ensure maximum portability, applicationsshould make sure that _XOPEN_SOURCE is defined by using eithercompiler options or<B>#define</B>directives in the source files, before any<B>#include</B>directives. Identifiers in this document may only be undefined using the<B>#undef</B>directive as described in<xref href=interface></xref>or<xref href=names></xref>.These<B>#undef</B>directives must follow all<B>#include</B>directives of any XSI headers.<p>Most strictly conforming POSIX and ISO C applications will compile on systemscompliant to this specification. However, an application which uses any ofthe items marked as an extension to POSIX and ISO C, for any purpose otherthan that shown here, may not compile. In such cases, it may be necessary toalter those applications to use alternative identifiers.<p>Since this document is aligned with the ISO C standard,and since all functionality enabled by the _POSIX_C_SOURCEset equal to 2should be enabled by _XOPEN_SOURCE, there should be no need todefine either _POSIX_SOURCE or _POSIX_C_SOURCE if _XOPEN_SOURCE isdefined. Therefore if _XOPEN_SOURCE is defined and_POSIX_SOURCE is defined, or _POSIX_C_SOURCE is set equal to 1 or 2,the behaviour is the same as if only _XOPEN_SOURCE is defined.However should _POSIX_C_SOURCE be set to a value greater than 2,the behaviour is undefined.<p>The<I>c89</I>and<I>cc</I>utilities recognise the additional<B>-l</B>operand for standard libraries:<dl compact><dt><B>-l curses</B><dd>This operand makes visible all library functions referenced in thisspecification, (except for those labelled ENHANCED CURSES and except forportions marked with the <SMALL>EC</SMALL> margin legend).If the implementation defines _XOPEN_CURSES and if the application defines the_XOPEN_SOURCE_EXTENDED feature test macro, then<B>-l curses</B>also makes visible all library functions referenced in this specification andlabelled ENHANCED CURSES and portions marked with the <SMALL>EC</SMALL> margin legend.</dl><p>It is unspecified whether the library<B>libcurses.a</B>exists as a regular file.<p>An application that uses any API specified as ENHANCED CURSES or relies onany portion of this specification marked with the <SMALL>EC</SMALL> margin legendmust define _XOPEN_SOURCE_EXTENDED = 1 in each source file or as part of itscompilation environment. When _XOPEN_SOURCE_EXTENDED = 1 is defined in asource file, it must appear before any header is included.<p>If the implementation supports the utilities marked<B>DEVELOPMENT</B>in the <B>XCU</B> specification, the<I>lint</I>utility recognises the additional<B>-l curses</B>operand for standard libraries:<dl compact><dt><B>-l curses</B><dd>Names the library<B>llib-lcurses.ln</B>,which will contain functions specified in this document.</dl><p>It is unspecified whether the library<B>llib-lcurses.ln</B>exists as a regular file.<h4>The X/Open Name Space (ENHANCED CURSES)</h4><xref type="3" name="names"></xref>The requirements in this section are in effect only for implementationsthat claim Enhanced Curses compliance.<p>All identifiers in this documentare defined in at least one of the headers, as shown in<xref href=headers></xref>.When _XOPEN_SOURCE is defined, each header defines or declares someidentifiers, potentially conflicting with identifiers used by theapplication. The set of identifiers visible to the application consists ofprecisely those identifiers from the header pages of the included headers, aswell as additional identifiers reserved for the implementation. In addition,some headers may make visible identifiers from other headers as indicated onthe relevant header pages.<p>The identifiers reserved for use by the implementation are described below.<p><ol type = 1><p><li>Each identifier with external linkage described in the header sectionis reserved for use as an identifier with external linkage if theheader is included.<p><li>Each macro name described in the header section is reserved forany use if the header is included.<p><li>Each identifier with file scope described in the header section isreserved for use as an identifier with file scope in the samename space if the header is included.<p><li>All identifiers consisting of exactly 2 upper-case letters.<p></ol><p>If any header is included, identifiers with the<B>_t</B>suffix are reserved for any use by the implementation.<p>If any header in the following table is included, macros with the prefixesshown may be defined. After the last inclusion of a given header, anapplication may use identifiers with the corresponding prefixes for its ownpurpose, provided their use is preceded by an<B>#undef</B>of the corresponding macro.<p><P><table bordercolor=#000000 border=1<tr valign=top><th align=left><b>Header</b><th align=left><b>Prefix</b><tr valign=top><td align=left><b><curses.h></b><td align=left>A_, ACS_, ALL_, BUTTON, COLOR_, KEY_, MOUSE, REPORT_, WA_, WACS_<tr valign=top><td align=left><b><term.h></b><td align=left>ext_</table><p>The following identifiers are reserved regardless of the inclusion of headers:<ol type = 1><p><li>All identifiers that begin with an underscore and either anupper-case letter or another underscore are always reserved forany use by the implementation.<p><li>All identifiers that begin with an underscore are always reservedfor use as identifiers with file scope in both the ordinaryidentifier and tag name spaces.<p><li>All identifiers listed as reserved in the <B>XSH</B> specification are reserved for use asidentifiers with external linkage.<p></ol><p>All the identifiers defined in this document that have external linkage arealways reserved for use as identifiers with external linkage.<p>No other identifiers are reserved.<p>Applications must not declare or define identifiers with the same name as anidentifier reserved in the same context. Since macro names are replacedwhenever found, independent of scope and name space, macro names matching anyof the reserved identifier names must not be defined if any associated headeris included.<p>Headers may be included in any order, and each may be included more than oncein a given scope, with no difference in effect from that of being includedonly once.<p>If used, a header must be included outside of any external declarationor definition, and it must be first included before the first referenceto any type or macro it defines, or to any function or object it declares.However, if an identifier is declared or definedin more than one header, the second and subsequent associated headersmay be included after the initial reference to the identifier.Prior to the inclusion of a header,the program must not define any macros with names lexically identicalto symbols defined by that header.<br><h4>Interfaces Implemented as Macros (ENHANCED CURSES)</h4>The requirements in this section are in effect only for implementationsthat claim Enhanced Curses compliance.<p>The following interfaces with arguments must be implemented as macros. Therelevance to the application programmer is that the `&' charactercannot be used before the arguments.<p><P><table bordercolor=#000000 border=1 align=center><tr valign=top><th align=center><b>Macros</b><th align=center><b>Chapter 4 Entry</b><tr valign=top><td align=left>COLOR_PAIR(), PAIR_NUMBER()<td align=left><i><a href="can_change_color.html">can_change_color()</a></i><tr valign=top><td align=left></B><I>getbegyx</I><B>(), </B><I>getmaxyx</I><B>(), </B><I>getparyx</I><B>(), </B><I>getyx</I><B>()<td align=left><i><a href="getbegyx.html">getbegyx()</a></i></table><p>The descriptions of headers in<xref href=headers></xref>list other macros, like COLOR_BLACK, that do not take arguments.<h3>Relationship to the XSH Specification</h3><h4>Error Numbers</h4>Most functions provide an error number in<I>errno</I>which is either a variable or macro defined in<i><a href="../xsh/errno.h.html"><errno.h></a></i>;the macro expands to a modifiablelvalueof typeint.<p>A list of valid values for<I>errno</I>and advice to application writers on the use of<I>errno</I>appears in the <B>XSH</B> specification.<a name="datatypes"><h3>Data Types</h3> </a><xref type="2" name="datatypes"></xref>All of the data types used by Curses functions are defined by theimplementation. The following list describes these types:<dl compact><dt>attr_t<dd>An integral type that can contain at least an unsigned short. The typeattr_t is used to hold an OR-ed set of attributes defined in<i><a href="curses.h.html"><curses.h></a></i>that begin with the prefix WA_.<dt>bool<dd>Boolean data type<dt>chtype<dd>An integral type that can contain at least an unsigned char andattributes. Values of type chtype are formed by OR-ing together anunsigned char value and zero or more of the base attributeflags defined in<xref href=curses.h></xref>that have the A_ prefix. The application can extract these components of achtype value using the base masks defined in<i><a href="curses.h.html"><curses.h></a></i>for this purpose.The chtype data type also contains a colour-pair. Values of typechtype are formed by OR-ing together an unsigned char value, acolour pair, and zero or more of the attributes defined in<i><a href="curses.h.html"><curses.h></a></i>that begin with the prefix A_. The application can extract these componentsof a chtype value using the masks defined in<i><a href="curses.h.html"><curses.h></a></i>for this purpose.<dt>SCREEN<dd>An opaque terminal representation.<dt>wchar_t<dd>As described in<i><a href="../xsh/stddef.h.html"><stddef.h></a></i>.<dt>cchar_t<dd>A type that can reference a string of wide characters of up to animplementation-dependent length, a colour-pair, and zero or moreattributes from the set of all attributes defined in this document.A null cchar_t object is an object that references a emptywide-character string. Arrays of cchar_t objects are terminated by anull cchar_t object.<dt>WINDOW<dd>An opaque window representation.</dl></blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
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